CVE-2026-64384Network attack vector

Kernel memory corruption via stale SMB response double-free

Published Jul 25, 2026 · Updated Jul 25, 2026

Double-free in the Linux Kernel SMB client allows remote attackers to corrupt kernel memory through replayed change-notify responses. SMB2_change_notify frees a response buffer after a replayable error, while SMB2_notify_init failure leaves its stale response type for cleanup to free again. An SMB client must connect to a malicious server that controls the replay and reconnection failure; allocator behavior determines whether corruption causes a panic, later crash, memory disclosure, or attacker-influenced kernel writes.

CVSS severity9.8
Critical
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double-free in the Linux Kernel SMB client allows remote attackers to corrupt kernel memory through replayed change-notify responses. SMB2_change_notify frees a response buffer after a replayable error, while SMB2_notify_init failure leaves its stale response type for cleanup to free again. An SMB client must connect to a malicious server that controls the replay and reconnection failure; allocator behavior determines whether corruption causes a panic, later crash, memory disclosure, or attacker-influenced kernel writes.

The record

CVE
CVE-2026-64384
Published
Jul 25, 2026
Updated
Jul 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=433042a91f9373241307725b52de573933ffedbf <5821f9dbb8b5b24391850a13418e633edd0fb003
  2. Affected versionversion=4f1fffa2376922f3d1d506e49c0fd445b023a28e <145f820dcbb2cced374f2532f8a61a44dce4a615
  3. Affected versionversion=4f1fffa2376922f3d1d506e49c0fd445b023a28e <52af1975f0dfae990c5a0e85872cc41be0e88a68
  4. Affected versionversion=4f1fffa2376922f3d1d506e49c0fd445b023a28e <901891513951bc8322ece754863909ea45af95c6
  5. Affected versionversion=4f1fffa2376922f3d1d506e49c0fd445b023a28e <d684f4134998085702009b94c35c2003fc9e72d3
  6. Affected versionversion=6.6.32 <6.6.145
  7. Affected versionversion=6.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=433042a91f9373241307725b52de573933ffedbf <5821f9dbb8b5b24391850a13418e633edd0fb003; version=4f1fffa2376922f3d1d506e49c0fd445b023a28e <145f820dcbb2cced374f2532f8a61a44dce4a615; version=4f1fffa2376922f3d1d506e49c0fd445b023a28e <52af1975f0dfae990c5a0e85872cc41be0e88a68; version=4f1fffa2376922f3d1d506e49c0fd445b023a28e <901891513951bc8322ece754863909ea45af95c6; version=4f1fffa2376922f3d1d506e49c0fd445b023a28e <d684f4134998085702009b94c35c2003fc9e72d3; version=6.6.32 <6.6.145; version=6.8

Published CVSS scores

9.8Linux Kernel CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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